OSLI Retina

February 2017

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96 Ophthalmic Surgery, Lasers & Imaging Retina | Healio.com/OSLIRetina Editorial Michael F. Marmor doi: 10.3928/23258160-20170130-01 Hydroxychloroquine Screening Alert: Change is in the Wind Michael F. Marmor, MD Hydroxychloroquine (HCQ) retinopathy is an infrequent but unfortunate con- sequence of long usage of the drug at excessive dosage. The American Acad- emy of Ophthalmology (AAO) published recommendations for screening in 2011 1 that reduced the risk of retinopathy, and these have been widely fol- lowed and publicized, including a recent review in OSLI Retina that showed classic field and optical coherence tomography (OCT) findings. 2 However, recent papers have shown that those guidelines are no longer optimal, and that screening practices must be changed. Updated 2016 AAO recommenda- tions 3 incorporate the latest information, and if followed, will allow longer usage of HCQ with even less retinopathy. This brief note is an alert to give OSLI Retina readers the key information to meet current practice standards, minimize risk, and detect HCQ retinopathy before there is significant visual loss. A classic "bull's eye" should never be seen again. RECENT FINDINGS ABOUT HCQ RETINOPATHY Dosage A survey of nearly 2,500 patients on long-term HCQ showed that real weight was a better indicator of dosage and retinopathy risk than ideal weight. 4 Old data suggesting that the drug fails to distribute in fat were ex- perimental and flawed, using small numbers of animals with non-human fat distribution. Human data show clearly that the best balance of dose versus risk is obtained when HCQ users stay below 5 mg/kg real weight. 4 The dose limit for chloroquine can only be estimated, and the suggested value is less than 2.3 mg/kg real weight. The biggest problem with the old ideal dosage guideline was that small women (a major part of the lupus population) were often overdosed, whereas less than 5 mg/kg real weight gives an accurate pre- diction of risk independent of body habitus. Because blood levels stabilize slowly, doses can be adjusted accurately by using one less tablet on certain days of the week. Dose Versus Duration The cumulative and annual risks of using HCQ depend upon a balance of daily dose and duration of use, and there is no magic number or cu- mulative dose that signifies retinopathy is imminent. HCQ can be contin- ued, no matter how long it has been used, as long as the visual fields and spectral-domain OCT (SD-OCT) remain normal. Kaplan-Meier curves 3,4 show that with proper dosage, the drug is remarkably safe for the first 10 years, but the risk rises with continued use. However, once a patient is found to be free of retinopathy, the incremental risk in the ensuing year is relatively low. High-Risk Factors Beyond dose and duration, the only major risk factors are preexisting mac- ulopathy, renal disease, and use of tamoxifen. 4 Older age, liver disease, and ABSTRACT: Recent studies have changed the manage- ment of hydroxychloroquine retinopathy. This editorial outlines a new standard. Es- timate dose by real weight, staying below 5 mg/kg. Asian patients may show initial damage outside the parafovea. Renal disease, maculopathy, and tamoxifen are major risk factors. Proper screening allows long usage and avoids bull's eye reti- nopathy.

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